The CTR also features a supplemental friction lock system that minimizes excessive stock movement for enhanced weapon stability* and an ambidextrous QD sling mount that will accept any push-button sling swivel. The Mil-Spec Model includes a standard 0.30" thick rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear.

NOTE: There are two basic sizes of M4 Carbine receiver extensions (buffer tubes): mil-spec and commercial-spec. If you have a commercial-spec extension on your rifle, make sure to order the Commercial-Spec CTR.